For introducing functional groups into a polymer, methods in which a functional group is introduced into a monomer are commonly practiced. However, such methods have not been suitable to design precise polymers due to difficulties in accurately specifying the number of functional groups and the introduction position.
On the other hand, it has been attempted to introduce a functional group into a polymerization initiator. In such attempt, however, a problem has been raised that the number of polymeric functional groups, etc. tends to be uneven in a polymer obtained by radical polymerization using a radical polymerization initiator containing a functional group, because a termination reaction occurs due to chain transfer or radical coupling.
In this regard, these events tend not to occur when using initiation systems that are used for a living radical polymerization, so that the number of functional groups and the introduction position can be accurately specified. Nevertheless, when, for example, synthesizing block polymers, especially multiple-block polymers, it is necessary to collect and purify a polymer every time a polymer consisting of a single component has been polymerized and thus there has been a problem of necessitating a considerably time-consuming work and high cost.
In case of a living anionic polymerization, when a polymerization initiator into which a protected functional group has been introduced is used, it will serve as a useful means for functionalization of a polymer, because the functional group is introduced into the initiation end so that the number of functional groups and the introduction position can be accurately specified. While some of such polymerization initiators are commercially supplied and available, there has been a problem depending on the solvent used that reactivity of the initiator becomes poor and results in a poor efficiency in initiating polymerization.
Further, in the production of a functional group-introduced polymer by a living anionic polymerization, there has been disclosed a production method using an adduct consisting of an organic alkali metal compound such as alkyllithium and a 1,1-diphenylethylene derivative having a functional group as a polymerization initiator (e.g., see Patent Documents 1-3), and a production method using a reaction of an anionic living polymer such as polystyryllithium and a 1,1-diphenylethylene derivative having a functional group (e.g., see Patent Document 4).
The 1,1-diphenylethylene derivative does not have a homopolymerization property and yields an addition reaction product in a quantitative ratio of 1:1 relative to the anionic species, hence it is advantageous in that a 1,1-diphenylalkyl group can be quantitatively introduced at the growth initiation end or the growth termination end of a polymer chain (e.g., see Non-patent Document 1).
All of these methods relate to an invention using a 1,1-diphenylethylene derivative. A 1,1-diphenylethylene derivative, however, does not seem to confer sufficient light resistance to a polymer because of its diphenyl structure. In addition, no method has been developed yet for using 1,1-diphenylethylene industrially.
Further, Patent Document 5 describes a copolymer that can have cinnamyl alcohol, which is used in the present invention, as a copolymer component. However, because the production method in Patent Document 5 employs cationic polymerization, it is difficult to quantitatively introduce cinnamyl alcohol at the growth initiation end or the growth termination end of a polymer chain unlike in a living anionic polymerization. This is because cinnamyl alcohol has a homopolymerization property.    Patent Document 1: Japanese Patent No. 2717587    Patent Document 2: Japanese Examined Publication No. 7-5649    Patent Document 3: Japanese Laid-open Patent Application No. 2006-69922    Patent Document 4: Japanese Laid-open Patent Application No. 4-11605    Patent Document 5: Japanese Laid-open Patent Application No. 2008-280378    Non-patent Document 1: Hayashi et al., Society Journal of “The Society of Rubber Industry, Japan”, 80 (1), 2007, p. 20-24